Author: avg
Date: Thu Oct 19 08:00:34 2017
New Revision: 324749
URL: https://svnweb.freebsd.org/changeset/base/324749

Log:
  MFC r324311: sysctl-s in a module should be accessible only when the module 
is initialized
  
  Sponsored by: Panzura

Modified:
  stable/10/sys/kern/kern_linker.c
  stable/10/sys/kern/kern_sysctl.c
  stable/10/sys/sys/sysctl.h
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/kern/kern_linker.c
==============================================================================
--- stable/10/sys/kern/kern_linker.c    Thu Oct 19 07:54:04 2017        
(r324748)
+++ stable/10/sys/kern/kern_linker.c    Thu Oct 19 08:00:34 2017        
(r324749)
@@ -285,7 +285,7 @@ linker_file_sysuninit(linker_file_t lf)
 }
 
 static void
-linker_file_register_sysctls(linker_file_t lf)
+linker_file_register_sysctls(linker_file_t lf, bool enable)
 {
        struct sysctl_oid **start, **stop, **oidp;
 
@@ -300,8 +300,34 @@ linker_file_register_sysctls(linker_file_t lf)
 
        sx_xunlock(&kld_sx);
        sysctl_lock();
+       for (oidp = start; oidp < stop; oidp++) {
+               if (enable)
+                       sysctl_register_oid(*oidp);
+               else
+                       sysctl_register_disabled_oid(*oidp);
+       }
+       sysctl_unlock();
+       sx_xlock(&kld_sx);
+}
+
+static void
+linker_file_enable_sysctls(linker_file_t lf)
+{
+       struct sysctl_oid **start, **stop, **oidp;
+
+       KLD_DPF(FILE,
+           ("linker_file_enable_sysctls: enable SYSCTLs for %s\n",
+           lf->filename));
+
+       sx_assert(&kld_sx, SA_XLOCKED);
+
+       if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
+               return;
+
+       sx_xunlock(&kld_sx);
+       sysctl_lock();
        for (oidp = start; oidp < stop; oidp++)
-               sysctl_register_oid(*oidp);
+               sysctl_enable_oid(*oidp);
        sysctl_unlock();
        sx_xlock(&kld_sx);
 }
@@ -427,7 +453,7 @@ linker_load_file(const char *filename, linker_file_t *
                                return (error);
                        }
                        modules = !TAILQ_EMPTY(&lf->modules);
-                       linker_file_register_sysctls(lf);
+                       linker_file_register_sysctls(lf, false);
                        linker_file_sysinit(lf);
                        lf->flags |= LINKER_FILE_LINKED;
 
@@ -440,6 +466,7 @@ linker_load_file(const char *filename, linker_file_t *
                                linker_file_unload(lf, LINKER_UNLOAD_FORCE);
                                return (ENOEXEC);
                        }
+                       linker_file_enable_sysctls(lf);
                        EVENTHANDLER_INVOKE(kld_load, lf);
                        *result = lf;
                        return (0);
@@ -686,8 +713,8 @@ linker_file_unload(linker_file_t file, int flags)
         */
        if (file->flags & LINKER_FILE_LINKED) {
                file->flags &= ~LINKER_FILE_LINKED;
-               linker_file_sysuninit(file);
                linker_file_unregister_sysctls(file);
+               linker_file_sysuninit(file);
        }
        TAILQ_REMOVE(&linker_files, file, link);
 
@@ -1618,7 +1645,7 @@ restart:
                if (linker_file_lookup_set(lf, "sysinit_set", &si_start,
                    &si_stop, NULL) == 0)
                        sysinit_add(si_start, si_stop);
-               linker_file_register_sysctls(lf);
+               linker_file_register_sysctls(lf, true);
                lf->flags |= LINKER_FILE_LINKED;
                continue;
 fail:

Modified: stable/10/sys/kern/kern_sysctl.c
==============================================================================
--- stable/10/sys/kern/kern_sysctl.c    Thu Oct 19 07:54:04 2017        
(r324748)
+++ stable/10/sys/kern/kern_sysctl.c    Thu Oct 19 08:00:34 2017        
(r324749)
@@ -226,6 +226,37 @@ retry:
 }
 
 void
+sysctl_register_disabled_oid(struct sysctl_oid *oidp)
+{
+
+       /*
+        * Mark the leaf as dormant if it's not to be immediately enabled.
+        * We do not disable nodes as they can be shared between modules
+        * and it is always safe to access a node.
+        */
+       KASSERT((oidp->oid_kind & CTLFLAG_DORMANT) == 0,
+           ("internal flag is set in oid_kind"));
+       if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
+               oidp->oid_kind |= CTLFLAG_DORMANT;
+       sysctl_register_oid(oidp);
+}
+
+void
+sysctl_enable_oid(struct sysctl_oid *oidp)
+{
+
+       SYSCTL_ASSERT_XLOCKED();
+       if ((oidp->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
+               KASSERT((oidp->oid_kind & CTLFLAG_DORMANT) == 0,
+                   ("sysctl node is marked as dormant"));
+               return;
+       }
+       KASSERT((oidp->oid_kind & CTLFLAG_DORMANT) != 0,
+           ("enabling already enabled sysctl oid"));
+       oidp->oid_kind &= ~CTLFLAG_DORMANT;
+}
+
+void
 sysctl_unregister_oid(struct sysctl_oid *oidp)
 {
        struct sysctl_oid *p;
@@ -768,7 +799,7 @@ sysctl_sysctl_next_ls(struct sysctl_oid_list *lsp, int
                *next = oidp->oid_number;
                *oidpp = oidp;
 
-               if (oidp->oid_kind & CTLFLAG_SKIP)
+               if ((oidp->oid_kind & (CTLFLAG_SKIP | CTLFLAG_DORMANT)) != 0)
                        continue;
 
                if (!namelen) {
@@ -1420,6 +1451,8 @@ sysctl_find_oid(int *name, u_int namelen, struct sysct
                        }
                        lsp = SYSCTL_CHILDREN(oid);
                } else if (indx == namelen) {
+                       if ((oid->oid_kind & CTLFLAG_DORMANT) != 0)
+                               return (ENOENT);
                        *noid = oid;
                        if (nindx != NULL)
                                *nindx = indx;

Modified: stable/10/sys/sys/sysctl.h
==============================================================================
--- stable/10/sys/sys/sysctl.h  Thu Oct 19 07:54:04 2017        (r324748)
+++ stable/10/sys/sys/sysctl.h  Thu Oct 19 08:00:34 2017        (r324749)
@@ -77,6 +77,7 @@ struct ctlname {
 #define        CTLFLAG_RD      0x80000000      /* Allow reads of variable */
 #define        CTLFLAG_WR      0x40000000      /* Allow writes to the variable 
*/
 #define        CTLFLAG_RW      (CTLFLAG_RD|CTLFLAG_WR)
+#define        CTLFLAG_DORMANT 0x20000000      /* This sysctl is not active 
yet */
 #define        CTLFLAG_ANYBODY 0x10000000      /* All users can set this var */
 #define        CTLFLAG_SECURE  0x08000000      /* Permit set only if 
securelevel<=0 */
 #define        CTLFLAG_PRISON  0x04000000      /* Prisoned roots can fiddle */
@@ -205,6 +206,8 @@ int sysctl_dpcpu_quad(SYSCTL_HANDLER_ARGS);
  * These functions are used to add/remove an oid from the mib.
  */
 void sysctl_register_oid(struct sysctl_oid *oidp);
+void sysctl_register_disabled_oid(struct sysctl_oid *oidp);
+void sysctl_enable_oid(struct sysctl_oid *oidp);
 void sysctl_unregister_oid(struct sysctl_oid *oidp);
 
 /* Declare a static oid to allow child oids to be added to it. */
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